Project Summary/Abstract Childhood maltreatment is a major risk factor for the development of psychiatric disorders as well as chronic and severe physical health problems across the lifespan. Emerging evidence suggests that epigenetic processes represent key mechanisms underlying the biobehavioral encoding of early adversity, and childhood maltreatment is associated with epigenetic changes in the genes that regulate the child stress response including neuroendocrine and immune system functioning. DNA methylation is a critical epigenetic process that regulates cell differentiation very early in fetal development and is responsive to environmental influences, including childhood maltreatment. Yet a basic understanding of how methylation longitudinally changes over time has yet to be achieved, with little knowledge of how childhood maltreatment affects these developmental trajectories. Likewise, although recent work suggests that methylation of stress sensitive genes contributes to child health outcomes, it is unknown how methylation longitudinally contributes to child health and behavior over time. The goals of the proposed research are: 1) to examine stability and change in methylation of glucocorticoid- and inflammatory-signaling genes from early to middle childhood; 2) to determine if childhood maltreatment is associated with stability and change in methylation over time; and 3) to investigate if methylation of glucocorticoid- and inflammatory-signaling genes is a mechanism linking childhood maltreatment to psychiatric outcomes, health outcomes, and pre-clinical indicators of malfunctioning in metabolic, inflammatory, and endocrine systems. Two hundred well-characterized, very high-risk, maltreated and non-maltreated children will participate. Assessments of early adversity, including childhood maltreatment, and child biopsychosocial health will be captured in early childhood (3 to 5 years) and middle childhood (9 to 11 years). Saliva DNA will be collected from children at each assessment to assess methylation of glucocorticoid- and inflammatory-signaling genes. Data analysis will focus on modeling longitudinal stability and change in methylation over time, as well as examining maltreatment as a predictor of stability and change in methylation. Methylation will also be examined as a mediator of the influence of maltreatment on child health outcomes. Understanding the longitudinal course of methylation across childhood will inform the basic science of epigenetic processes, as well as refinement of interventions to enhance resilience among children with early adversity.